1 ton duelly no load mileage

[Sparkyinak]

Hi all

My first post here. My wife and I are contemplating becoming professional nomads. We pretty much have our one ton duelly blueprinted however I'm hung up on the axle ratio. We will be going with the club cab 4x4 6.7 Cummins and 6 speed AISIN auto trans.

We haven't picked our camper yet however it will be a 5th wheel 20,000 class. We will not be on the road full time. Maybe 1-3 months out of the year but living out of the RV all the time. The 4.10 is the obvious towing champ however, I'm carious and bit concern about fuel economy when we are not towing. With the 800+ to 900 ft/lb of torque, I'm wondering if the 3.73 would be worth the trade off

To the one ton duelly/cummins owners. What is you no load mpg around town and highway and what's your gear ratio? If you have a 3.73, how does your 1 ton handle heavy loads in the 20k lb range?

 

[xrsman]

My question is what kind of fifth are you looking at that'll be 20K lbs??

Sent from my SM-G920W8 using Tapatalk

 

[Kwhite]

I have a 3:73 axle and ave around 17-18 in town i tow 14,000 lb like a champ! I would go with the 3:73

 

[avolnek]

My folks own a 2013 crew cab long box 3500 dually with 3.73 gears. they usually net around 16 empty on the highway and 10ish pulling an 18,000 pound 5th wheel.

my folks have no complaints on their rig what so ever... even took it from eastern nebraska up into canada on a 3 week vacation... this year alone they put 10,000 miles of camper travels.

 

[nmroper]

Hi all



My first post here. My wife and I are contemplating becoming professional nomads. We pretty much have our one ton duelly blueprinted however I'm hung up on the axle ratio. We will be going with the club cab 4x4 6.7 Cummins and 6 speed AISIN auto trans.



We haven't picked our camper yet however it will be a 5th wheel 20,000 class. We will not be on the road full time. Maybe 1-3 months out of the year but living out of the RV all the time. The 4.10 is the obvious towing champ however, I'm carious and bit concern about fuel economy when we are not towing. With the 800+ to 900 ft/lb of torque, I'm wondering if the 3.73 would be worth the trade off



To the one ton duelly/cummins owners. What is you no load mpg around town and highway and what's your gear ratio? If you have a 3.73, how does your 1 ton handle heavy loads in the 20k lb range?

I've pulled a 20k# toy hauler from coast to coast and border to border for over 70k miles with 3:73. Mileage I've seen is 8-10 hauling depending on head winds/terrain, and 12-15 w/o trailer. It should be noted that per Rams Specs your towed trailer weight is much lower with 3:73s. OBTW I have 97k miles on truck with no issues to date. However, I recognize that I'm likely overtaxing the truck and could be more likely to see premature mx issues.

 

[DannyMK2]

id say go with the 4.10's if you have the opportunity. unloaded your mileage might suffer slightly, maybe 1mpg or so depending on the driving you do. its nothing drastic. definitely not drastic enough that i would sacrifice towing power over, imo.

 

[BossHogg]

id say go with the 4.10's if you have the opportunity. unloaded your mileage might suffer slightly, maybe 1mpg or so depending on the driving you do. its nothing drastic. definitely not drastic enough that i would sacrifice towing power over, imo.

The difference is 75 MPH for the 3:73 and 68 MPH with the 4:10s at 1,800 engine RPM in sixth gear. Rule number one for MPGs, it starts with your foot.

People have a way to always error on the side of more power but most don't understand how to calculate that out. To fix that problem, Cummins offers a PC application called PowerSpec (https://cumminsengines.com/powerspec) that allows you to enter your parameters and will tell you the best axel ratio for your needs with respect to engine RPMs.

Just for an example, I'm pulling around 15,000 pound fiver, sweet spot for me is between 1,600 and 1,800 engine RPMs. To get that, (I have a SRW so no choice on axle ratio) neither the 3:42 or 3:73 would get me in my 55 MPH (surface streets) cruising RPM range with out dropping to fifth gear.

Take PoweSpec for what it is worth.